Diagnose by symptom

My car is a 99 ford taurus dohc 3.0 liter 6 cylinder with 135, 000 miles on it. It was hesitating alot in the last 2 weeks like it wouldnt change gears when pulling off from a light or when I came to a complete stop and then hit the gas to continue. It was idleling high especially when hot. The check engine light came on 3 days ago and yesterday I put gas in it an immediately after that I was going on interstate and it started to hesistate real bad then it slowed down and I hit the gas and I watched the rpms going down and everytime I hit gas it would not accelerate then I pulled over to shoulder put my car in park then turned it off checked all fluids they were fine then I turned it back on it cranked up and I gave it some gas it revved up I took it out of park and into drive it set idle and wouldn't move I put it in reverse it would go backwards either but it did come on and the engine is purring and all other areas were working the electric windows, ac, stereo, lights etc adn horn : :